Dairy farmers working in seasonal calving systems do not improve their sleep in late lactation compared with the spring calving period

Context A lack of sleep (<7 h/night) has potential negative cognitive and physical outcomes for all human beings. In seasonal calving dairy farm systems, the early starts associated with milking, along with the high workload over the calving period, put dairy farmers at risk of insufficient sleep. Previous research has highlighted insufficient sleep over the calving period; however, it is unknown whether farmers’ sleep changes later in the lactation season when the pressures of calving have been alleviated. Additionally, the effect of roster, working hours and farm system elements on sleep has not been investigated in a dairy farming context. Aims The aims of this study were to: (1) compare sleep quantity and quality of dairy farmers on seasonal calving farms between the spring calving period and late lactation; and (2) identify effects of roster, working hours and farm system elements on sleep metrics. Methods In this study, 38 dairy farmers working on seasonal spring calving farms wore a sleep measuring sensor during the night over the spring calving period (8 July to 8 September 2023; 62 days) and late lactation (1 April to 31 May 2023; 60 days). Roster and working hours data were obtained for each participant, along with farm system information for each farm. Partial least square regression analysis was undertaken to model the effects of period (spring calving vs late lactation), farm system factors, working hours and roster factors on sleep metrics. Key results Total per person daily sleep time was insufficient over both periods (6.6 h/day spring calving; 6.7 h/day late lactation). Participants slept on average 48 min more on days off compared with days when they were working. Those that worked longer days also had decreased sleep time. Conclusions Participants were not achieving better sleep outcomes in the late season when compared with the spring calving period in seasonal calving dairy systems. Implications Data from this novel study can be used to inform farmers of factors associated with increasing sleep quantity and quality, and be utilised by farm management when setting rosters and designing the working day (including choosing milking times), as well as informing dairy workplace policy around farmer wellness and workplace design.